The toothbrush, consisting of a head of tightly clustered bristles mounted on a handle, is a tool used to clean the teeth and gums. The long handle allows for cleaning of hard-to-reach areas of the mouth. Usually toothpaste is used with the toothbrush to increase the effectiveness of the toothbrush. Toothbrushes are made of various sizes, bristle textures, etc. Most dentists suggest using soft bristled toothbrushes due to harder ones damaging enamel.
Pre-dating toothbrushes people used a...

Heterodontosaurus, meaning "different toothed lizard", is a genus of dinosaur from the Early Jurassic Period of what is now South Africa. The type species, H. tucki, was found in the Upper Elliot Formation of the Hettangian age (199 to 196 million years ago). Two species are known.
This herbivorous dinosaur ate mostly plants despite having canines. It was a small ornithischian reaching a total length of 3 feet. It had a long, narrow pelvic bone which was like more advanced ornithischians....

A pivoted catch designed to fall into a notch on a ratchet wheel so as to allow movement in only one direction (e.g. on a windlass or in a clock mechanism), or alternatively to move the wheel in one direction.